New Fluorescent Probe Offers Breakthrough in Monitoring Mitochondrial Viscosity

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A recent study tested a new mitochondria-targeting fluorescent probe, known as Mito-CDM, to see if it can improve the monitoring of mitochondrial viscosity. The study, which was recently published in Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, showcases how technological innovation is contributing to the advancement of biological analysis (1).

The mitochondria plays a major role in cellular health and energy production (1). Known as the “powerhouse of the cell,” the mitochondria burns the calories we consume with the oxygen we take in to provide energy to the human body (2). This is why abnormal changes in mitochondrial viscosity are associated with various diseases, including neurodegenerative disorders and inflammation (1). However, tools capable of reliably monitoring such changes have been limited.

In this study, the researchers designed the new Mito-CDM probe to improve monitoring through the incorporation of several new features. For example, the probe contains a N,N-diethylaminophenyl group that acts as the viscosity-sensitive molecular rotor, while the pyridinium cation provides mitochondrial targeting ability (1). These two components allow the probe to respond to changes in viscosity by altering the fluorescence output. As the viscosity of its surrounding environment increased from 0.55 centipoise (0% glycerol) to 950 centipoise (100% glycerol), Mito-CDM demonstrated a linear fluorescence response with an R² value of 0.9957 (1). Notably, in high-viscosity media, the probe exhibited a dramatic 166-fold fluorescence enhancement at 586 nm, underscoring its exceptional sensitivity (1).

The research team also evaluated its biological utility. To do so, they used HeLa cells subjected to nystatin and lipopolysaccharide-induced inflammation, which are two conditions known to alter mitochondrial viscosity (1). Then, by using the Mito-CDM probe, the researchers successfully tracked viscosity changes during these inflammatory responses, confirming its potential as a powerful tool for studying cellular stress and disease mechanisms (1).

According to the authors, Mito-CDM’s design not only enhances mitochondrial imaging but also paves the way for deeper insights into how viscosity changes affect cellular function. By shifting from an “off” fluorescence state in low-viscosity conditions to an “on” state in higher-viscosity environments, the probe provides researchers with a direct and real-time method to visualize changes that were previously difficult to quantify (1).

The development of Mito-CDM represents a significant step forward for molecular probes aimed at mitochondrial research. As mitochondrial dysfunction is linked to a wide range of health conditions, from aging to cancer, tools like Mito-CDM are expected to support both fundamental research and the development of therapeutic strategies (1).

References

1. Wang, L.; Song, W.; Li, F.; et al. Mitochondria-immobilized fluorescent probes for viscosity and cellular imaging. Spectrochimica Acta Part A: Mol. Biomol. Spectrosc. 2026, 346, 126847. DOI: 10.1016/j.saa.126847
2. The University of Queensland, Australia, Mitochondria: What Are They and Why Do We Have Them? UQ.edu.au. Available at: https://qbi.uq.edu.au/brain/brain-anatomy/mitochondria-what-are-they-and-why-do-we-have-them (accessed 2025-08-28).